1. Field of the Invention
This invention relates to liquid detergent compositions.
2. Description of the Prior Art
To date, most shampoos and light duty household detergent products have been based on the combination of an anionic surfactant and a surface active agent serving as a foam promoter or stabilizer. Exemplary of the anionics for these applications include sodium lauryl sulfate (SLS), sodium lauryl ether sulfate (SLES) and linear alkyl benzene sulfonate (LAS). Generally, the foam promoter is a tertiary amine oxide or an alkanolamide, either of the so-called superamide or of the Kritchevsky type.
All of the aforementioned surface active agents and particularly the anionics are severe eye irritants and are capable of causing mild to moderate skin irritation to some sensitized persons. Lately, there has been a trend toward substantially ameliorating the irritant effects of such compositions by using the anionic in conjunction with an amphoteric type surfactant and combining these compounds with a nonionic surfactant in the form of an ethoxylate of a partial polyol ester of a higher fatty acid.
The state of the art products of this type, such as the so-called baby shampoo formulations, range in the category of "mildly irritating" in accordance with the Draize eye irritation test. While it would be desirable to provide even blander systems in this respect than are now available, the overriding desiratum, however, is that of obtaining like systems which affords the formulator acceptable latitude in regulating viscosity characteristics of the final products. Most detergent compositions of the type herein concerned are marketed as water solutions containing from about 10 to 30 percent active content. About the only means for regulating viscosity at the indicated range of solids content for the prior art systems necessitates the inclusion of common salt. But this expediency is self-defeating inasmuch as the added salt significantly increases the eye irritation properties of the product.